3.5 Effect in endothelial impairment protection and angiogenesis both in vitro and ex vivo
To assay the protective effect of PEG-FGF2 conjugates against endothelial impairment in vitro , we explored tube-forming activity in HUVECs exposed to high glucose (HG, 33 mM) medium treated with compounds 5 , 6 , and7 , or controls (PBS and FGF2) for 72 h. We found significantly impaired tube-forming activity in HUVECs exposed to HG, with significant enhancement by compound 6 compared to native FGF2 (Figure 6 A and C ). This result showed that improved tube-forming activity by compound 6 in HUVECs exposed to HG.
To further characterize the endothelial angiogenesis function of PEG-FGF2 conjugates, an ex vivo model was next performed (Brillet al. , 2004). The aortic rings from C57BL/6 mice were cultured in medium containing HG (33 mM) with either FGF2 or PEG-FGF2 conjugates. Aortic rings cultured in HG medium exhibited dramatically impaired sprouting function, but the sprouting function was well preserved by FGF2 and compound 6 (Figure 6 B and D ). The tube lengths of samples incubated with compound 6 were longer than those of samples incubated with native FGF2. Compounds 5 and7 promoted angiogenesis to some degree. These results confirm that compound 6 exhibits the strongest vascular regeneration activity in HG medium, implicating its potential application in diabetic wound healing.